An Unusual Night for CB

by Mario Filippi (N2HUN)

December 2nd was an unusual night for CB (Citizen’s Band) radio, as the band was open late (0030 GMT) when I turned on the President Washington CB radio just to see who was on. First stop was Channel 19 (27.185 MHz), the trucker’s channel, where the QRM was high, due to the skip from the many truckers on the channel. Earlier in the day this channel was very quiet as was the rest of the band. The fact that Channel 19 was pinning the S meter after dark was a big hint that the band might be open. And it certainly was!

Uniden President Washington AM/SSB Base Station

Being a CB’er from back in the 70’s (call sign KBN-8387), this band was my first serious introduction to two-way radio communication, and after 40+ years it’s still an enjoyable experience to listen in to the local, and sometimes DX chatter. For the most part the CB band mimics 10 meters, basically open during the day (except when sunspot numbers are low) and closed at night. That’s the usual drill, but Mother Nature doesn’t always go by the playbook and sometimes the band is opened at the darnedest times, sometimes even after midnight!

So this evening around 8:30 EST the President Washington CB base station was fired up and CB operators were heard in Maine, Illinois, and as far as Wisconsin, definitely what would be considered out of the ordinary range of CB, which is generally several miles. Now FCC rules still state that it’s illegal to communicate over 155 miles but it’s a non-issue when the band’s open. For the most part, AM is used on most of the channels but you’ll find LSB activity on Channel 36 (27.365 MHz). And when the band gets busy and crowded, you’ll hear LSB QSOs from Channels 36 – 39 (27.365 – 27.395 MHz) as sidebanders spread out among the channels so that they can work each other through the QRM.

To get a better idea of what the CB band “looks” like during a band opening, a spectral scan of the band (26.965 – 27.405 MHz) would be useful. This can be achieved using an SDR dongle, such as the RTL-SDR.com version which is a diminutive broadband receiver with an analog to digital converter and covers from about 26 – 1670 MHz. Used in conjunction with an up-converter (from Nooelec), software such as SDR# (SDR Sharp) and a computer (Smartphone apps are available also) you’ll be able to put up a spectral scan of the band as well as hear what’s happening.

RTL-SDR.com dongle – a small broadband receiver covering all modes

Nooelec’s Ham It Up RF Upconverter expands dongle’s receiving range to the entire HF and MW band

As the old adage goes, “a picture is worth a thousand words” so tonight the SDR dongle, along with SDR# software was fired up to get an idea of how many stations were on during the opening. The antenna used was an S9 43 foot vertical, the same one I use for HF. Using the dongle, it’s an easy feat to visualize the entire CB band on the spectral scan, which is a plot of frequency (X axis) versus signal strength (Y axis). The top half of the screen is the spectral scan and the lower half is the “waterfall” which is a time lapse recording of the spectral scan.

Screenshot of CB Band (wide red stripe) during tonight’s opening.

Normally at this time of night a spectral scan of the CB band would be flat-lining, but as you can see there are plenty of stations conducting QSOs, with the stronger stations having higher peaks and more intense tracings on the waterfall. Seeing the entire CB band visually gives one lots of information such as what channels are active, how many stations are on, what stations might be running higher power (limit is 4 W AM, 12W PEP SSB output), whether outbanders are active or whether DX stations outside the US are partaking of the opening.

Over the years I’ve heard the CB band open beyond midnight and on a winter’s night during a snowstorm. Some openings have lasted for hours. Last year, using the mobile CB, operators from Europe, the Caribbean, and as far away as Australia were heard during my commute to work. At the opposite extreme some days all you’ll hear is ignition noise, hihi. It’s a lot like 10 meters and even a bit like 6 meters; you never know what surprises Mother Nature has in store. Spin the tuning dial over to the CB band and take a listen one of these days.

Thank you so much, Mario!

Only a few weeks ago, I noticed on my SDR’s wideband spectrum display that the 11 meter band was very active. I started listening around and was absolutely amazed at how organized some of the nets were and how reliable skip was. Signals were blanketing all of the eastern US and even into the west. Sometimes I think there are openings on the 10 meter band, for example, but there are so few users there in comparison, no one notices. The CB frequencies are pretty much always active, when conditions are favorable for DX, everyone instantly notices!

]]>http://swling.com/blog/2016/12/guest-post-an-unusual-night-for-cb/feed/5Tecsun PL-680: Just How Sensitive is This Radio?http://swling.com/blog/2016/12/tecsun-pl-680-just-how-sensitive-is-this-radio/
http://swling.com/blog/2016/12/tecsun-pl-680-just-how-sensitive-is-this-radio/#commentsThu, 08 Dec 2016 21:24:45 +0000http://swling.com/blog/?p=22753More than two months ago, in the Mount Evelyn DX Report I posted a review of the Tecsun PL-680 portable receiver, entitled Tecsun PL-680 Beats Expectations. In that article, I pointed out many of the positives and a few of the flaws surrounding the unit. At the end of the review, I promised I would do some sensitivity tests on the radio.

Well, I finally got around to completing the tests, and the results are in. Below is a YouTube video showing a practical demonstration of the receiver’s capabilities in this area of performance.

The portable Tecsun PL-680 receiver is a hot little radio! As these tests show, it appears to be very sensitive to weak signals. Here, we put the little 680 up against one the best HF transceivers on the market today – the Yaesu FTDX3000 transceiver. The receiver in the 3000 is quite brilliant! And it has all the “bells-and-whistles” to make it even better at digging out weak signals and reducing adjacent channel interference.

However, in these tests we turn off all the fancy facilities on the FTDX3000 and just run the two receivers side by side to see how the 680 compares. We use the same antenna and we plug both radios into the same external speaker, adjusting as close as we can to equal volume and tone quality. We select a variety of shortwave broadcast stations over a range of frequencies from the 60 through to the 16 meter bands. I think you’ll discover that the Tecsun is really a very good performer when it comes to sensitivity!

[Additionally] I have started the prequels to Media Network’s return in 2017.

I found a great cassette sent to me by Africa media correspondent Richard Ginbey in 1989. Richard was a music presenter, first in South Africa, later moving to Windhoek. But I guess his passion was listening to his shortwave radio. And with nothing more than a cassette recorder he put together some fascinating portraits of broadcasting history as observed from a listeners’ perspective.

Richard also made features which traced the history of broadcasting in Africa, making some recordings which track the path to independence for many countries. I’m pretty sure many of these bandscans from the 1980’s and before have long since disappeared from official archives. So, here’s a chance to listen again to Richard Ginbey’s media view. I’ve put together several episodes back to back. Enjoy.

Thank you so much for sharing this, Jonathan. I might contact you soon about adding those cassette recordings to the shortwave archive. Absolutely priceless stuff! And the return of Media Networks? Please keep us informed!

]]>http://swling.com/blog/2016/12/media-network-updates-and-1999-interview-with-acting-abc-general-manager-mike-bird/feed/0The role of radio intelligence before the Pearl Harbor attackhttp://swling.com/blog/2016/12/the-role-of-radio-intelligence-before-the-pearl-harbor-attack/
http://swling.com/blog/2016/12/the-role-of-radio-intelligence-before-the-pearl-harbor-attack/#respondWed, 07 Dec 2016 21:47:22 +0000http://swling.com/blog/?p=22745

Photograph taken from a Japanese plane during the torpedo attack on ships moored on both sides of Ford Island shortly after the beginning of the Pearl Harbor attack. (Source: WikiMedia Commons, Public Domain)

Many thanks to SWLing Post contributor, Michael Guerin, who writes:

Interesting article from the US Naval Institute on the role of radio intelligence before and during the December 7 attack.

“The key to the success of the Japanese attack on Pearl Harbor-specifically, what enabled the Pearl Harbor Striking Force to reach its launch point undetected (and totally unsuspected) by the Americans-was Tokyo’s radio denial-and-deception actions. Significantly, these activities simply were not just a “bag of tricks” meant to bemuse U.S. naval radio intelligence. Rather, they constituted a function of the change in Japanese strategy and were meant to convince the Americans that there had been no change from defensive to offensive intentions.”

Personality of the Year 2016 on RRI

We would like to ask you which person you think left their imprint on the world in a positive way in 2016. We are preparing to designate, based on your options, “The Personality of the Year 2016 on RRI”. Will this person be a politician, an opinion leader, a businessman, an athlete, an artist, a scientist, or even a regular person with a special story? It’s up to you! We would also want to ask you why you picked that particular person.

You can send your answers, as usual, by commenting on our website, at rri.ro, by e-mail at engl@rri.ro, on our Facebook, Google+, Twitter and LinkedIn profiles, by fax at 00.40.21.319.05.62, or by post, at 60-64, General Berthelot street, sector 1, Bucharest, area code 010165 (PO Box 111), Romania.

The “Personality of the year 2015 on RRI” was German Chancellor Angela Merkel.
The “Personality of the year 2016 on RRI” will be announced on January 1st 2017.

Above is a sample SSTV image received during a pass in April 2006 from KC4ALE on ISS Fan Club

An early Christmas gift for space enthusiasts around the world is coming again this year with Slow-Scan TV images from the International Space Station. Reception varies wide;y from location to location, but there are usually at least several passes which will yield good results.

Here is the announcement with pertinent details:

SB SPACE @ ARL $ARLS011

ARLS011 Slow-Scan Television Transmissions Scheduled from ISS

ZCZC AS11

QST de W1AW

Space Bulletin 011 ARLS011

From ARRL Headquarters

Newington, CT December 6, 2016

To all radio amateurs

SB SPACE ARL ARLS011

ARLS011 Slow-Scan Television Transmissions Scheduled from ISS

Slow-scan television (SSTV) transmissions from the International Space Station (ISS) are scheduled for December 8-9. The SSTV images will be transmitted from RS0ISS on 145.800 MHz FM as part of the Moscow Aviation Institute MAI-75 Experiment, using the Kenwood

TM-D710 transceiver in the ISS Service Module.

MAI-75 activities have been scheduled on December 8, 1235-1800 UTC, and December 9, 1240-1740 UTC. These times correspond to passes over Moscow, Russia. ISS transmissions on 145.800 MHz FM use 5-kHz deviation, and SSTV transmissions have used the PD120 and PD180 formats.

The ISS Fan Club website at http://www.issfanclub.com/ can show when the space station is within range of your station. On Windows PCs the free application MMSSTV can decode the signal. On Apple iOS devices, use the SSTV app available through iTunes.

There are a number of software program available for SSTV reception in addition to the ones mentioned above. It would be interesting to hear from folks who have used SSTV programs with their impressions. Good hunting!

Yet Another !&*%$! Noise Source

The past few days, I have noticed higher than usual noise levels, generally on the lower frequencies, and particularly on the longwave band, including the 285-325 kHz DGPS band, where I run nightly SDR recordings, to later process the data and decode and detect DX DGPS stations using my Amalgamated DGPS app.

Thinking back to what new electronics devices have been added to the house, two came to mind, a new cable modem, and a new ethernet switch. The switch is up here in the shack, so it seemed to be a likely candidate. The switch is a D-Link DES-1008E 8-Port 10/100 Unmanaged Desktop Switch. It uses a mini USB port for power, using either the included AC adapter, or power from a USB port. When I installed it, I decided to not use the AC adapter, but rather a USB port on my UPS, figuring it was better to not add yet another potentially noisy switching power supply to the mix.

The test was easy, I just unplugged the power to the switch. Sure enough, the noise vanished. Great, the switch is a RFI generator. Or is it? As another test, I plugged it into a port on a USB hub. No noise. Hmm… so it seems that the noise is indeed from the USB port on the UPS. I did not notice any increase in the noise floor when I got the UPS a few months ago, but It’s something I should look into again, just to be sure. The UPS is a CyberPower CP1350PFCLCD.

Here’s a waterfall from the SDR, showing the DGPS band, 280-330 kHz. You can see where I changed the power to the switch from the UPS USB port to the USB hub, the bottom part of the waterfall is when the switch was still powered by the UPS (click to enlarge it):

I still have a noise source just above 305 kHz to hunt down.

Update

I decided to see what I could do to improve things, and reduce the noise floor.

Here is the baseline, after no longer powering the switch from the UPS:

First, I relocated the AFE822 away from the computer and rats nest of assorted cables behind it, powered from an HTC USB charger:

The squiggly noise around 305 kHz vanished!

I then switched to an Apple USB charger / power supply, as their products tend to be a bit better made:

Another improvement, the overall noise floor is a bit less now.

But can we do better? I then switched to an older USB hub for power to the AFE822, that I thought might be better filtered:

I then changed to a linear supply plugged directly into the AFE822. I don’t notice any obvious improvement? Maybe it even looks like a little more noise? Difficult to tell. You can see a DGPS station popped up on 304 kHz while I was switching things around, between the last two tests, it was likely Mequon, WI.

Thank you for sharing this, Chris! I find a wideband spectrum/waterfall to be such a useful tool for tracking down sources of noise. Not only can you “see” the noise, but you can measure its bandwidth and identify what portions of the dial it affects.